Sporting Lisbon have disciplined defender Marcos Rojo, after the Argentina international refused to train and handed in a transfer request in order to try and force through a move to Manchester United. The Premier League club are thought to have made a €20 million (£16m) bid for Rojo as manager Louis van Gaal seeks to add to his defensive options ahead of the start of the Premier League season on Saturday.

But Sporting have no intention of making it easy for Manchester United to secure a player who only missed one game as Argentina finished as runners-up in this summer’s World Cup. The Portuguese club’s president, Bruno de Carvalho, as well as revealing that he had disciplined Rojo, insisted that he will not be influenced by the actions of the 24-year-old or want-away teammate Islam Slimani.

“They will not play next weekend,” he told Sporting TV, according to Portuguese publication Record. “This will take as long as is needed. It the situation doesn’t change, it will end up with the players seeing out their three-year contracts.”

It remains to be seen if Sporting’s position is any more than mere posturing in an attempt to secure a higher fee. It is doubtful, however, that Manchester United would be getting value for money should they increase their offer. While he impressed at left-back during the World Cup, he has not always convinced as a player belonging at the top level in a Sporting shirt. Though he could also feasibly play at wing-back, it is likely that Rojo is being targeted by Van Gaal as a left-sided center-back.

It is an area where the Dutch coach is keen to strengthen, with just Phil Jones, Jonny Evans and Chris Smalling as established options to fill the three center-back slots in his 3-4-1-2 formation. United missed out on the signing of Thomas Vermaelen last week when the former Arsenal captain instead joined Barcelona. And an always ambitious pursuit of Borussia Dortmund’s Mats Hummels now looks even more unlikely to pay off after he was announced as the German club’s new captain, and with manager Jurgen Klopp again dismissing the frequent rumors linking his defender and new vice-captain Marco Reus with exits.

“When I broke the news to the team, I told them that it's not because they are frequently linked with other clubs but despite those links,” he said, reports ESPN FC. “One thing has nothing to do with the other. But should this somehow lead to it [the players staying beyond 2015], that wouldn't be so bad. That they keep getting linked to other clubs, and moreover with laughable transfer fees attached to their names, had nothing to do with it."

While Manchester United recorded a victory in their final preseason match against Valencia on Tuesday, Van Gaal’s first match in charge at Old Trafford also reaffirmed that his squad is short of the balance and quality required to return the club to the Premier League summit. Van Gaal recently stressed his side lacks a top quality wide option, while praising a man who United have been linked with throughout the summer, Ángel di María .

When the president of perceived front-runners for the Argentina international, Paris Saint-Germain, claimed that they were pulling out of the race in recent days, it was thought that United had a clear run at the player. However, The Independent has reported that the feeling at Old Trafford remains that the player is headed for the French champions. The Daily Telegraph has a slightly different take, instead stating that Manchester United could be poised to make a £50 million bid for a man who was a key part of Real Madrid lifting the Champions League last season but whose place has been put in doubt by the arrival of James Rodríguez.

Speculation also continues about Daley Blind. Like Rojo, the Netherlands international can also play at center-back and on the left side of the defense. His versatility also stretches to defensive midfield. The Ajax man admitted earlier this week that he would consider a move, while Van Gaal has stated his admiration for the qualities of Dutch players. According to the Daily Mail, a reunion between the pair could be close, with the tabloid reporting that Manchester United are confident of landing the 24-year-old for a fee of around £20 million.